THE PERITONEUM 379 



the stomach is full, the spleen is pushed further back and loses contact with 

 the liver. 



The spleen is attached by two peritoneal folds, the suspensory' lij^anient and 

 the gastro-splenic omentum. The suspensory ligament (Lig. suspensorium lienis) 

 attaches the base to the left crus of the diapln-agm and the left kidney; it contains 

 a quantity of elastic tissue. The part which passes to the diaphragm is the liga- 

 mcntum phrenico-lienale, and blends with the gastro-phrenic ligament; the i)art 

 whicii g()(>s to tlie kidney is termed the ligamentum renolienale. The gastro- 

 splenic omentum (Lig. gastrolienale) passes from the hilus to the left part of the 

 great curvature of the stomach. It is narrow above, where it joins the suspensory 

 ligament; l)elow it becomes much wider ami is continuous with the great omentum. 



Small globular or lenticular ma.sses of splenic tissue may be found in the gastro-splenic 

 omentum. They are termed accessory spleens (Lienes accessorial). 



Structure. — The spleen has an almost complete serous coat. Subjacent to 

 this and intimately united with it is a capsule of fibrous tissue (Tunica albuginea), 

 which contains many elastic fibers and some imstriped nuisctilar tissue. Numerous 

 trabeculae (Tral)ecuhe lienis) are given off from the deep face of the capsule and 

 ramify in the substance of tiie organ to form a suiii)orting network. In the inter- 

 stices of this framework is the spleen pulp (Pulpa lienis). a dark red, soft, grumous 

 material. This is supported by a delicate adenoid reticulum, and contains numer- 

 ous leukocytes, the large splenic cells, red blood-corpuscles, and pigment. The 

 pulp is richly supplied with blootl. The branches of the splenic artery enter at 

 the hilus and pass along the tral^eculse. The arteries which enter the pulp have a 

 sheath of lymphoid tissue, which collects on the vessel wall at certain points, form- 

 ing small lymph nodules, the so-called Alalpighian corpuscles (Noduli lymphutici 

 lienales). These are visible to the naked eye as white sjiots, about as large as the 

 head of a pin. The blood passes into cavernous spaces lined by endothelium 

 which is continuous with the cells of the reticulum of the pulp. From these the 

 veins arise. The splenic vein runs in the hilus in company with the artery and 

 nerves, and joins the posterior gastric vein to form a large radicle of the portal vein. 



Blood-supply. — Splenic artery. 



Nerve-supply. — Splenic plexus. 



THE PERITONEUM 



The general disposition of the peritoneum has been described, and other facts 

 in regard to it were mentioned in the description of the viscera. It is now desirable 

 to study it as a continuous whole. ^ (Figs. 256, 257, 278, 279.) 



We may consider the peritoneum as consisting of two sacs — a greater and a 

 lesser. The greater sac lines the greater part of the abdominal cavity, and covers 

 most of the viscera which have a peritoneal investment. The lesser sac is an 

 introversion or recess of the greater sac, formed during the development of the vis- 

 cera. The two sacs communicate by a relatively narrow passage, termed the 

 epiploic foramen of Winslow (Foramen epiploicum) . This opening is situated on the 

 visceral surface of the liver above the portal fissure. It can be entered by passing 

 the finger along the caudate lobe of the liver toward its root. Its dorsal (or an- 

 terior) wall is formed by the caudate lobe and the posterior vena cava. Its ventral 

 (or posterior) wall consists of the pancreas, the gastro-pancreatic fold, and the portal 

 vein. The walls are normally in contact, and the passage merely a potential one. 

 It is usually about four inches (ca. 10 cm.) in length. It is narrowest at the right 



^ The student is strongly recommended to study the peritoneum of a foal or other small 

 subject when the opportunity occurs, as in these the viscera are easily handled, and the course 

 of the peritoneum can be followed without difficulty. 



